One of the early centers of American shale drilling is roaring back tolife, boosted by a building boom of petrochemical plants, fertilizer factories and gas-export terminals along the Gulf Coast.The Haynesville Shale, a giant natural-gas field in northwestLouisiana, was one of fracking ’s hottest spots a decade ago. But it

fizzled out about five years ago as gas prices plunged and drillersfocused on finding oil next door in Texas. Now, the Haynesville isbeing reborn as companies with longstanding positions in the area,such as Chesapeake Energy Corp.,, and newcomers seeking opportunity rush back in and drill again.

Gas production from the Haynesville has risen more than 20% so farthis year, to more than 7 billion cubic feet a day from less than 6 billion in January, according to the U.S. Energy Department. The number of rigs active in northern Louisiana parishes and the Texas portion of the field has more than tripled in the past year to 44,